Space telegraphy.



L. DE FOREST SPACE TELEGRAPHY.

APPLICATION FILED JAN. 29, 1907.

943,969. Patented Dec. 21,1909.

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L. DE FOREST.

SPACE TELEGRAPHY.

APPLIOATION FILED nuns, 1901.

Patented Dec. 21, 1909.

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APPLICATION 111,121) JAN. 29, 1907.

943,969. Patented Dec. 21, 1909.

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SPACE TBLEGRAPHY. APPLICATION rum) 11111.29, 1907.

943,969, Patented Dec. 21, 1909.

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L. DE FOREST.

SPACE TELEGRAPHY.

APPLICATION FILED umze, 1907.

Patented Dec. 21, 1909.

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l whic LEE ms ronnsr, on NEW YORK, N. Y., ASSIG OBQBY- Masai. assmnmanrs' ro :mi ronns'r RADIO 'rnnnrnonn '00.,4 conrona rron or mw YORK.

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* Patented Dec. 21,- 1909.

Application tiled January29,-19o7. sem nojssaees.

To all whom it mag 'iconce m;

Be it known that I, LEE DE zen of the United States, and a'resident ofNew York, in the county. of New York andv State ofNe'w. York, haveinvented a new arid useful Improvement Space Telgraph'y, of which thefollowing is a specification;

The present invention relates; to space telegraph or telephonetransmitting. systems. .lhe' object-of the invention is to provide adischarger for acircuit, open or closed, containing an electricalcapacity, an electrical.

condenser or other capacity, which shall be of very low electricalresistance after the prime' discharge, which shall permit ojf a I re,,a1; and constant spark-frequency, and

- for: maintaining between said electrodes a.

condition of. high ionic conductivity. In the drawings whi h accompanyand form apart of this specification-I have illustrated in diagramseveralf embodiments of 'thedischar'ger which. constitutes the'subjectmatter of my-invention and several arrange- 'm 'ents of circuits showinghow said discharger may be employed'm practice. I

In the drawings Figures 1,2, 5, 6, 8', 11, 12,- 13 and 14-. representelectromagnetic Wave -radiating systems. Fig. 1* represents a side Qelevation ofthe discharge-r shown. in Fig. 1

2 as}; section of the discharger shown in -Fig. 2 taken on, th e line 041; Fig. 3

.re resents-partly in perspective and partly he line a'a of Fig. 4; Fig.5 is a diagr'am-- matic view show ng a radiating system wherein a sin leelectrodeis associated with a filament within the evacuated vessel. Fig.6 is afsimilar view showing two filaments in the evacuated vessel. Fig.7 is :an elevation of still another modification. Fig. '7 is a sectiontaken on theline aa of, Fig. -7. Fig. 9 represents substantially thesame type of discharger shown in Fig. 4 provided with meansgformaintaining a constant temperature within the evacuated vessel. Fig. 1 0

i: represents substantially the same type" of shall have certain othlfadvantages looking inthe direction of thearrow. Fig.

.- sides arranged on Y idischargershown Fig. 2 provided with- FOREST, acitimeans for'maintaini'ng a, constant tempera-. ture within theevacuated vessel. Fig.'l0

is a section'tak'en on the line H of 'Fig'. 10.. Fig. 11i's'adiagrammat'ic view show-mg aco radiating system shpwingthedischarger in the groundconnectlonof the antenna system. Fig. 12 is.a view similar to Fig. 11. showing a modified "arrangement of radiatingsystem with, the discharger in the- 5 antenna circuit.- Fig. 13 is asimilar view showing a .magnet associated. with the dis charger. Fig. 14is a similar view showing a grid electrode associated with a plateelec-- trode-and a filame t' in the evacuated vessel. In the figures, isan antenna, L IlSgflIl in-, 'ductance, Efis an earth connection, 'MM andM are transformers, C is a condenser, K is a key, m is amic'rophonictransmitter, A 'is .asourbe of vibratory electromot'ive force, D is asource of unidirectional .electromotive -force,"S is a spark-gap,R is are sistance, B, B, B," are batteries, I is an insuvlator, a nd "Lis achoke-coil. linFig. 1, F is an a? cuated vessel of glass or othersuitable material in which are sealed two electrodes G G which as shownare plates. T he'filament H which maybe sealed in said vessel F in theusual manner is .ar

.rangedwith its p1anenormal to the axis-of 8.5

.the electrodes and is of a suliic'ien'tly large diameter to prevent.the dischargeof the. condenser 0 across the ga I between G G fromstriking the same.- --T i'e filament H is heated preferabl toincandescence by the batteries. B whic preferably are insulated I by theinsulators I.' r

' In Fig. 2 'thespark electrodes J J are. shown as spheres andthe-filament is arranged at oneside of the axis of said elec 95. trodeswith its plane parallel to said axis. Preferably the distancebetween-the filament and -the electrodes 'is greater than the distancebetween the electrodes themselves.

' "In-Fig. 3, the electrodes N N are shown as 1 concentric cylinders andthe filament-H may be lacedinside the inner cylinder N'.

' n Fig. 4, the electrodes 0 O are plates of 1 platinum .or othersuitable material, an ranged end on and the filament H is arranged as'shown withits plane'normal to the plane of said lates.and,w1th,1tsf-two ltheNSide, of the 'ga .in-

tervening between theadjacent edges? sa'id plates.

In Fig. 5, the electrode P is a plate of platinum or other suitablemetal and the electrode H. is a very heavy filament preferably of metalcoated with an oxid of an alkali metal.

In Fig. 6, both electrodes are formed of substantially the samedischarger which is shown in-Fig.- 2, the magnet N-S is an ranged todeflect the ionic stream produced by heating the electrode H across thegap between: the electrodes J J In'Fig. 9, which shows substantially thesamedischarger which is illustrated in Fig. 4, the spines T T areconnected to the plates 0 O and project outside the vessel F so as toincrease the radiation of heat from the interior of the vessel andthereby maintain the temperature of said interior as constant as may be.

In Fig. 10, the electrodes U U are hollow pipes provided with twopassage-ways u u for water or other cooling liquid to the end that thetemperature of the interior of the vessel F maybe regulated.

In Fig. 1, the circuit C L G. G is the usual oscillation circuit of aspace telegraph transmitting system, the condenser C of which is chargedby the alternating or vibratory current developed by the" generator Aand discharges across the gap between the electrodes G G, therebysetting up high frequency electrical oscillations, the energy of whichmay be translated to the antenna V in any large ohmic resistance.

charger is to be used in such a circuit or m suitable manner. I havefound that by evacuating'the vessel F and, preferably, by maintainingtherein a very high temperature, the resistance offered by thegapbetween the electrodes G G may be materially reduced, so that there willbe a minimum of damping in the oscillation circuit. and hence.

a 'maximum of persistency. This I believe to be due' chiefly to the factthat the conduction across the gap is maintained by ions and not by theheated metallic-dust vapors. In cases where spheres or balls areemployed I prefer to use balls of relatively .55

large diameter. It is advantageous sometimes to coat the filament withoxids of the alkali metals.

In Fig. 2 I have shown an oscillating circuit in the nature of asinging-arc circuit in which the condenser is charged by-a circuitcontaining a direct electromotive force and IVhen my ,dis-

the regular singing-arc circuit, I prefer the form of (.lischarger shownin F 1g. 6, which form I find tobe very eflicient because of theexceedingly lowresistance of the gap between the two heated filamentsand to.

permit of a very regular spark-frequency. When the spark-frequency isequal to the frequencynatural to the oscillation circuit and to that ofthe antenna system, in other words when the oscillations are continuous,it is of course very important that said spark frequency should beconstant. In fact the ditliculty of obtaining a-constant frequency witha singing-a'rc circuit is, so far as'l am aware, the chief reason whysuch circuits are not more generally used.

In the system of circuits shown in Fig. 5,

electrical pulsations are developed in the eircuit C L P H, theconductivity of the discharger shown in said system being unilateral.

lines lead to a source of electromotive forcewhich maybe as shown eitherin Fig. 1 or in Fig. 2. v

In Figs. '11, 12, 13 and 14, which represent electromagnetic waveradiating systems, the antenna is associated with the oscillatingcircuit S C I by means of the transformer M, the secondary of which isincluded in series with said antenna. In each of said figures there isincluded in series with said antenna, and preferably at a point havingpractically zero potential with earth, a discharger of one of theseveral types hereinbefore described. As set forth by me in priorLetters Patent No. 836,015, Nov. 13, 1906, variation produced in saidantenna atsaid point will effect variations in the waves radiatedtherefrom. For this purpose the microphone m connected in series withthe battery B may be' employed as shown. In Figs. 11, 12 and 14,the-circuit in which cur rents are varied by the operation of saidmicrophone, is associated directly with the discharger while in Fig. 13the said circuit is associated with the magnet l which is sur-,

tenna and interposed between the filament H and plate P. I

In Figs. 13 and 14 thedotted linesleac'fto any suitable source ofelectromotive force.

It will be understood that many modifications may be made by thoseskilled in the art in the 'discharger which forms the subject matter ofthe present invention and that said-discharger is capable of use in avariety of systems of circuits other than those which I have hereindescribed. Accordingly I do not wish to limit myself either to the exactnwchanical embodiments of said discharger. o: to the use of the same inany of the systems of circuits which for the purpose of more fullydisclosing my invention 1 have specifically described.

I claim:

1. The combination with a source of electrical energy and a circuitincluding an electrical capacity, of a discharger comprising an.evacuated vessel, two electrodes sealed therein, and means maintaining aheated gas in said vessel.

2. The-combination with a source of electrical energy anda circuitincluding an electrical capacity, of a discharger comprising anevacuated vessel, two electrodes sealed therein and means formaintaining a condition of ionic conductivity between said electrodes.

3. The combination with a source of electrical energy and a circuitincluding an electrical capacity, of a discharger comprising anevacuated vessel, two electrodes sealed therein, a conducting membersealed within said vessel and located in proximity to said electrodesand means for heating said member.

4. The combination with a source of electrical energy and a circuitincluding an electrical capacity, of a discharger comprising anevacuated vessel, two electrodes sealed therein, a conducting membersealed within said vessel and located in proximity to said electrodes,means for heating said member, and magnetic means for deflecting towardsaid electrodes the ionic stream produced by so heating said member.

5. The combinationwith a source of electrical energy and a circuitincluding an electrical condenser, of a discharger comprisin anevacuated vessel, two electrodes sealed therein and means maintaining aheated gas in said vessel.

. 6. The combination with a source of electrical energy and acircuitincluding an electrical condenser, of a discharger comprising anevacuated vessel, two electrodes sealed therein, and means formaintaininga conditiorci1 of ionic conductivity between said electro es.

7. The combination with a source of elec-.

trical energy and a circuit including an electrical condenser, of adischarger comprising an evacuated vessel, two electrodes sealedtherein, a conducting member sealed within said vessel and located inproximity to said electrodes, and means for heating said member.

8. The combination with a source of electrical energy and a circuitincluding an electrical condenser, of a discharger comprising anevacuated vessel, two electrodes sealed therein, a'conducting membersealed within said vessel and located in proximity to said electrodes,means for heating said member, and magnetic means for deflecting towardsaid electrodes the ionic stream produced by so heating said member.

9. An oscillation circuit including a condenser and the primary of atransformer in combination with a source of electrical energy adischarger for said condenser comprising an evacuated vessel, twoelectrodes sealed therein and means maintaining a heated gas in saidvessel.

10. The combination with a source of electrical energy and anoscillating circuit including a condenser and the primary of atransformer, of a discharger for said condenser comprising an evacuatedvessel having two electrodes sealed therein, and means for maintaining acondition of ionic. conductivity between said electrodes.

11. An oscillation-circuit including a condenser and the primary of atransformer in combination with a source of electrical en ergy, adischarger for said condenser comprising an evacuated vessel, twoelectrodes sealed therein, a conducting member sealed within said vesseland located in proximity to said electrodes and means for heating saidmember.

12. An oscillation-circuit including a condenser and the primary of atransformer in combination with a source of electrical energy adischarger for said condenser comprising an evacuated'vessel, twoelectrodes sealed therein, a conducting i'nember sealed within saidvessel and located in proximity to said electrodes, means for heatingsaid member, and magnetic means tor deflecting toward said electrodesthe ionic stream produced, by so heating said member.

In testimony whereof, I have hereunto subscribed my name this 21th dayof December, 190G.

LEE DE FOREST. Witnesses Hans W. Gonrzn, OSCAR F. SHAW, Jr.

